Post written by Choong-Kyun Noh, MD, PhD, from the Department of Gastroenterology, Ajou University School of Medicine, Suwon, South Korea.

Helicobacter pylori infection is associated with gastric diseases such as gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. As H pylori eradication can reduce gastric cancer incidence and metachronous gastric cancer rate after endoscopic resection, accurate detection of H pylori infection is very important.

Although the rapid urease test (RUT) is a representative invasive method for detection of H pylori infection, its sensitivity varies with the sampling site and conditions. In addition, sampling errors are a major problem. Because this weakness becomes more prominent after eradication owing to reduced bacterial load and clustering, RUT is not preferred as a monitoring test after eradication.

H pylori is a noninvasive bacterium that lives in the mucus layer, so the essential component for the urease test is the mucus itself, with mucosal and submucosal tissues actually not needed for diagnosis. For this reason, RUT does not detect H pylori directly but rather indirectly via detection of urease, which the organism expresses.

This raises the question: Why perform tissue sampling even when the sampling error is known? We developed and introduced RUT using the sweeping method in 2020,¹ showing higher sensitivity in diagnostic performance than that of RUT using the tissue sampling method.

In the present study, we compared these 2 methods after H pylori eradication. We attempted to confirm diagnostic performance of the sweeping method, which demonstrated very high sensitivity even when the bacterial load was low after treatment. Thus, we examined whether RUT combined with the sweeping method is a valid monitoring test for patients who underwent H pylori eradication therapy and require endoscopy.

Our sweeping method shows higher sensitivity and accuracy than that of the conventional method for H pylori detection after the standard first-line eradication treatment. The time taken for detecting H pylori infection using the sweeping method was 2.6 times faster than that of the conventional method. The risk of discrepancy between the results of the methods increased near the cutoff point of the urea breath test (UBT) values, and the sweeping method showed high sensitivity in this “gray zone.”

Given its high sensitivity, our H pylori detection method is expected to replace conventional methods involving biopsy sampling. RUT using the sweeping method is expected to play an important role, especially in patients who require endoscopy after eradication. Owing to this method, the H pylori sampling process has changed such that when using an existing commercial RUT kit, endoscopists can easily perform the examination and obtain rapid results.

The sweeping method also can be performed for H pylori detection in patients with bleeding tendencies and coagulopathy. In addition, this method could be an alternative option to UBT in patients requiring endoscopic evaluation.

Because the sweeping method is highly sensitive, false-positive results are identified and need to be clarified through culture studies. Further research is needed to standardize the appropriate swab material and the number and location of the sweeps.

This method is cost-effective and not associated with adverse events, such as bleeding because of biopsy sampling. Therefore, RUT with the sweeping method can replace the existing conventional method as a confirmatory test after H pylori eradication and is a potential alternative to UBT in patients who require endoscopic evaluation.

Study concept and process of the sweeping and conventional methods. A, Illustration of the study concept. B, Endoscopic image of the sweeping method and mimetic image of swab material. C, Illustration and actual image showing placement of the swab material in the rapid urease test kit. D, Sampling area of the sweeping and conventional tissue sampling methods in the antrum (left) and corpus (right).

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1. Noh CK, Lee GH, Park JW, et al. Diagnostic accuracy of “sweeping” method compared to conventional sampling in rapid urease test for Helicobacter pylori detection in atrophic mucosa. Sci Rep 2020;10:18483. ↩︎